Method of making tire-casings



WI E. WILLIAMS.

IVIETHD 0F MAKING TIRE CASINGS.

APPLICATION FILED FEB. 21. I9I7.

1,346,623, y PaIenIea July 13,1920.

PATEN OFFICE.

' 'i n. EBASTS WILLIAMS, OF CHICAGO, ILLINOIS, LASSIGNOR TO THE FIRESTONE AND RUBBER COMPANY, OF AKRON, OHIO, A CORPORATION' OF OHIO.

METHOD OF MAKING TIRE-CASINGS.

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Specification of Letters Patent. aftgmted July 139 lggqyo Application led February 21, 1917. Serial No. b 265.

To all 'who/m t may concern Be it known that I, WILLIAM E. WIL- LIAMS, a' citizen of the United States7 residing in the city of Chicago, county of Cook, State of Illinois, have invented certain' new and useful Improvements in Methods of Making 'Iire-Casings, of which the following is a specification.

In the manufacture of tire casings made from woven fabi-1c, 1t is the common practicc to cut rubber impregnated woven fabric on the bias, or at an angle of 45 to assemble the cut strips in a continuous length and to form the length of fabric into a roll which is placed in the tire making machine. rIhe fabric is usually drawn from the roll to a revolving core through'any suitable friction or tensioning mechanism which, in coperation with the revolving core, stretches the fabric over the crown or. central portion of the core. It is necessary to stretch the fabric over the core in order to enable the same to Aconfermato the curvature of the core and the use of' bias fabric enables this shaping to readily and easily be donel without wrinkling. l i

, 4So far as lmown to me there have been friction brake arrangement. rllhis method is open to several very serious objections. rIhe amount'oftension necessary to be placed on the frictioni roll requires adjustment, which introduces the human element into the tire manufacture. A friction brake will not afford any means for compensating for the varying widths of plies used in the manufacture of tires, nor for the difference in stretchability due to temperature and freshness of the rubber coating or friction. A second method of stretching the fabric on the-core is to pass it around a roll which is connected with the shaft on which the core is carried or with some other driving element of the machine, the gearing being so correlated that the stretching roll travels at a rate of speed which is less than the core shaft, whereby the fabric is stretched on the core. This `method is perhaps superior to the first method outlined above as there is no variation traceable to differences in the various plies, but no provision .has been made for the increasing thickness of the carcass as the plies are built up on the core. The speed of rotation of the core bearsl a constant ratio to the speed of rotation of the roll over which the fabric is passing, but the peripheral speed of the surface which is pulling the fabric over the stretching roll increases with each revolution of the core, with the result that each ply is stretched a little more than the preceding one with a consequent inequality in the strains and'stresses which each ply is called upon to carry.

To correct-this evil in the llast outlined method a further third practice'has been developed, which consists in driving or retarding the stretching roll not from the core shaft, but'from a roller bearing upon and driven from the periphery-or surface ofthe core. This has taken care of the increased periphery of the tire as it is constructed but has, in turn, introduced several elements into the stretching of the fabric which make the method unreliable. 'Ihe driving or retarding roller running on the surface ofthe core has been subjected to the action fofeach splice or overlap lin the ply, the

'which-in turn has been transmitted to th fabric.

In each of the last two methods of stretching as explained above a further disturbing element which has affected thestretch has been that each splice' on the core in passing up under the ply as it oes to the core has caused a variation in lt e stretch of the fabric. All of the methods adaptable for machine manufacture have re uired the use of a continuous strip of bias fa ric.' After a ply has been laid it is necessary to. out the fabric between the core and the stretching roller, which has released the end of the fabric from the tensioning pulland has relieved the stretch on the last end of the ply, which introduces a further element of uncertainty andi ositive inaccuracy in the stretch of the abrio. Further, in passing from a flat stretching roll to a curved rotating core it has been found advisable to intro'- duce an element into the machine to remove longitudinal wrinkles or folds which occur between the stretching roll and the core incidentpto the reshaping ofv the fabric. This better tire carcass than by any in practice known to me. The percentage of stretch is readily and accurately determinable and l am enabled to distribute the stretch uniformly throughout each ply.

While the' description contained in this application has referred to Woven fabric such as used in the manufacture of fabric tires, the invention is not confined to operations on this type of material, but may be used on any form of fabric from Which tires can be made.

lt is understood that changes and modifications may be made in the method as shown herein, Without departing from the invention or sacriiicing any of its benefits.

Claims:

1. The method of making tire casings from fabric, comprising forming said fabric into a ring of smaller circumference than a core, exerting an expanding force on the ring, relaxing said force simultaneouslyat all points about the ring and allowing the center of the ring to shape itself to the center of the corel, and then shaping the skirts of the fabric to thecore.

2. The method of making tire casings, comprising forming fabric into a ring, expanding the ring to a circumference greater than the outer periphery of a core, placing the ring While in expanded condition about the core, relaxing the fabric so that it will contract about the core.

3. The method of making tire casings, comprising forming fabric into a ring, expanding the ring to a circumference greater than the outer periphery of a core, placing the ring While in expanded condition about the core7 centering the ring with respect to the core, and relaxing the fabric so thatl it Will contract about the core.

4. lin the making of fabric tire casings, the steps of taking a core and a ring of fabric material which in its normal untensioned condition is of less diameter than the diameter of the core, expanding the ring of material to a diameter exceeding that of the core, telescopically assembling the core and the ring in its expanded condition, and permitting the ring to contract upon the core.

5. A method for use in the manufacture of tires, comprising formingV tire material into a ring, expanding the ring to a circumference greater than the outer periphery of the core, placing the ring While in ex anded condition about the core, and relaxing the material so that it will contract on to the core.

WILLIAM ERASTUS WILMS. Witnesses:

ALBERT el. Snnsnn, M. L. Loomnn. 

